During the last two decades of the nineteenth century, male sterility developed into an object of considerable medical attention. Microscopic analysis of sperm was employed as a new diagnostic tool to determine whether the childlessness of a marriage was due to the sterility of the husband. Past infections with gonorrhoea came to be seen as the single most important cause of this problem. This article explores the history of sperm testing by applying Actor-Network-Theory (ANT). It shows how new biological knowledge about the mechanisms of reproduction, the spread of laboratory methods in medicine, the growing availability of microscopes, failures in the treatment of female infertility and interactions between doctors and patients combined to make sperm analysis feasible. Empirically the article focuses on Germany. As a historical case study, the article contributes to a growing body of literature on the medicalisation of male bodies. This research, the article argues, challenges the familiar notion that throughout history, and especially since the eighteenth century, the female body was pathologised, while the male body was regarded as unproblematic and stable. Furthermore, by turning to ANT, the article takes up an approach which is very prominent in the field of science and technology studies and which promises to go `beyond constructivism'. The article raises the question of why it is that gender history seems to be reluctant to question social constructivism. Taking the well-known narrative of the one-sex/two-sex model as an example, the article shows that constructivism continues to be attractive despite much criticism.
